1. Field of the Invention
This invention relates generally to grinding and shaping apparatus, and more particularly to apparatus for shaping and polishing non-molten glass.
2. Description of the Prior Art
The material known as "glass" is in reality a supercooled liquid. It is extremely malleable and may be easily formed into nearly any shape when it is heated to softening or molten points. However, when glass is allowed to cool, it frequently becomes extremely brittle since it does not form a cohesive crystalline structure as do true solids. These properties make glass a very easy material to work with while molten or at high temperatures, but make it fragile and difficult to work with at normal atmospheric temperatures.
Since it is frequently necessary to perform various operations on glass at normal temperatures, it is necessary to derive methods for performing these operations which minimize the danger of chipping, shearing, or shattering the material. Not all operations can take place with the molten glass. Some of these involve the smoothing out of irregularities, the polishing of the glass surface, and particularly in the instance of special-purpose glass, the forming and modifying of sections for optical and spectral reasons.
The art of making beveled glass objects such as windows, lampshades, and displays, has become extremely popular in recent years. Enrollment in classes teaching persons how to work with beveled glass has jumped substantially and the interest in the art has reached a very high level.
The majority of prior art attempts to provide means for beveling and polishing glass have been in the nature of abrasive surfaces, either stationary surfaces against which the particular piece of glass is rubbed, or moving surfaces such as a belt sander or a rotating grindstone. Various modifications have been made in order to attempt to minimize the danger of damage to the glass surface. Efforts have been particularly notable in the fields of mirror and lends grinding. Examples of prior art means of beveling or grinding a cooled glass surface are demonstrated in U.S. Pat. No. 1,664,300 issued to B. F. Kelly, U.S. Pat. No. 852,626, issued to C. Schwartz and J. Bortzner, and in German Pat. No. 2250052.
The prior art has paid scant attention to machines or methods for effectively beveling a glass surface. The term "beveling" as used in relation to glass means to take a sheet, workpiece or pane of glass of a certain thickness and to gradually taper the thickness of the sheet towards the edges such that the edge portion of the pane is thinner than the central portion. This beveled edge creates an aesthetically pleasing form for art glass. The tapered surface junction with the flat surface also creates a light diffraction through the glass resulting in a light scattering spectral array.